The ravages of coastal erosion are widespread throughout the world. Beaches are destroyed or seriously damaged by continued erosion. In some areas the coastline recedes to such an extent that valuable land is lost and buildings fall into the sea.
Many attempts have been made to prevent or at least to reduce coastal erosion. These have included the erection of stone jettees, breakwaters and sea walls and the planting of variously shaped barriers along a beach or coastline. Further it has been proposed to anchor floating wave barriers in the water near the shoreline. However, these devices have not come into wide use apparently because of high cost and ineffectiveness.
On the other hand, a serious problem arises from the deposit of slit and sand in waterways, anchorages and harbors and alongside docks. For example channels and other waterways may become so filled by sand or silt that they are no longer navigable by vessels of a size for which they are intended. Likewise deposits of sand or silt adjacent piers or docks may make it impossible for vessels of substantial draft to reach them. Such deposits can be removed by dredging but this is an expensive operation. By reason of limited funds, the U.S. Coast Guard has ceased to dredge areas which they previously maintained. By reason of this, waterways, anchorages, piers and docks have been rendered virtually useless by reason of deposits of sand or silt.